In recent years, the number of ophthalmic surgeries such as cataract surgeries where an intraocular lens (IOL) is delivered internally within an eye of an individual has steadily increased. IOLs have been developed and inserted into various locations of the eye and can be used to supplement or correct the vision provided by the natural crystalline lens of the eye or can replace the natural crystalline lens of the eye. Lenses that supplement or correct the vision without replacing the natural crystalline lens are typically referred to as Phakic Lenses while lenses that replace the natural crystalline lens are typically referred to as Aphakic lenses. Phakic lenses can be located within the anterior chamber (AC) of the eye (AC Phakic lenses) or the posterior chamber (PC) of the eye (PC Phakic Lenses).
While IOLs have provided millions of individuals with improved eyesight, IOLs can also exhibit drawbacks. In particular, IOLs can be a cause of ophthalmic maladies such as secondary cataracts or posterior capsule opacification (PCO).
To assist in avoiding PCO, therapeutic agents such as anti-inflammatories or anti-proliferatives can be administered to an eye after insertion of an IOL therein. These therapeutic agents are typically delivered via topical delivery methods such as ointments or ophthalmic drops. Such methods, however, have at least two significant drawbacks. First, it can be difficult for these topically delivered therapeutic agents to reach target locations within the eye since portions of the eye can act as significant physiologic barriers that inhibit the penetration of the therapeutic agents into the back of the eye. Second, the efficacy of these topical delivery methods is typically dependent upon an individual's compliance with a prescribed regimen for application of the ointment or drops to the eye.
In view of these drawbacks, it would be highly desirable to provide an ophthalmic device that is inserted within the eye and that delivers desired amounts is of a therapeutic agent over a period of time after cataract surgery. Such a device could be used to deliver agents that assist in avoiding PCO. Moreover, insertion of such a device within the eye, after surgery or at another time, could additionally or alternatively be used to deliver therapeutic agents that inhibit other ophthalmic diseases or maladies such as glaucoma, macular edema, retinopathy, macular degeneration, chronic inflammation, infection or the like.
To effectively develop such a device, there needs to be a mechanism by which the therapeutic agent is continuously or periodically released from the device over the desired period of time. However, for extend release time periods, control over the release of the therapeutic agents can be extremely difficult. Advantageously, a relationship has been discovered between particular ophthalmic materials and release of therapeutic agents from those materials and that relationship can be exploited to provide for desired release periods.